Iodine → 5-Bromo-[2,2']bithiophenyl

HRID 433846

Reaktionsgleichung

Reaktionsgleichung von HRID 433846
[Br:1][C:2]1[S:3][CH:4]=[CH:5][CH:6]=1.II.Br[C:10]1[S:11][C:12](Br)=[CH:13][CH:14]=1>C1COCC1.C1C=CC(P(C2C=CC=CC=2)[C-]2C=CC=C2)=CC=1.C1C=CC(P(C2C=CC=CC=2)[C-]2C=CC=C2)=CC=1.Cl[Pd]Cl.[Fe+2]>[Br:1][C:2]1[S:3][C:4]([C:10]2[S:11][CH:12]=[CH:13][CH:14]=2)=[CH:5][CH:6]=1.[S:3]1[CH:4]=[CH:5][CH:6]=[C:2]1[C:10]1[S:11][C:12]([C:2]2[S:3][CH:4]=[CH:5][CH:6]=2)=[CH:13][CH:14]=1

Komponenten

7

Edukt 3

HCID 807IodineHCID 138512-Bromothiophene3×HCID 184532,5-Dibromothiophene

Produkt 2

HCID 650672,2':5',2''-TerthiopheneAusbeute 16 %HCID 6400655-Bromo-[2,2']bithiophenylAusbeute 57 %

Reagenzien, Katalysatoren, Lösungsmittel 2

HCID 178418228Bis(cyclopenta-1,4-dien-1-yl(diphenyl)phosphane);dichloropalladium;iron(2+)KatalysatorHCID 8028TetrahydrofuranLösungsmittel3×

Versuchsvorschrift

A solution of 2-bromothiophene (4.967 g, 24.92 mmol) in 5 ml dry THF was added dropwise to a mixture of Mg-turnings (752 mg, 30.94 mmol) and a small iodine crystal in 25 ml dry THF. After addition of about 1 ml of the bromothiophene solution, the reaction started and the mixture heated to reflux. The rest of the bromothiophene solution was added dropwise to the reaction, and the mixture was stirred for 1 hour at reflux. The reaction mixture was then transferred with a syringe into an addition funnel and was added slowly during 3 hours to an ice-cooled mixture of 2,5-dibromothiophene (8.206 g, 33.91 mmol) and PdCl2(dppf)2 (250 mg, 0.306 mmol, complex with CH2Cl2 1:1) in 50 ml dry THF. This mixture was stirred for 2 hours at 0° C. and for 16 hours at room temperature. The solvent was evaporated in vacuo and the residue was suspended in EtOAc and washed with saturated NaHCO3 solution and brine. The aqueous layers were extracted with EtOAc and the organic layers were dried (MgSO4). Evaporation of the solvent and purification by FC (hexanes) gave 4.229 g 5-bromo-2,2′-bithiophene (6, FIG. 3) (17.25 mmol, 57%) and 1.216 g 2,2′:5′,2″-terthiophene (7, FIG. 3) (4.896 mmol, 16%) as yellow solids. 6:1H-NMR: 7.22 (dd, J=5.2, 0.8, 1 H), 7.11 (dd, J=3.6, 0.8, 1 H), 7.00 (dd, J=5.2, 3.6, 1 H), 6.96 (d, J=3.9, 1 H), 6.91 (d, J=3.9, 1 H) 13C-NMR: 138.9, 136.4 (2s), 130.6, 127.8, 124.8 (3d), 124.3 (s), 124.0, 123.8 (2d) EI-MS: 246 (100, [M]+, 81Br), 244 (88, [M]+, 79Br), 165 (39), 121 (53).

Aufarbeitung

  1. temperaturethe mixture heated to reflux
  2. temperatureat reflux
  3. customThe reaction mixture was then transferred with a syringe into an addition funnel
  4. temperaturecooled
  5. stirringThis mixture was stirred for 2 hours at 0° C. and for 16 hours at room temperature
  6. customThe solvent was evaporated in vacuo
  7. washwashed with saturated NaHCO3 solution and brine
  8. extractionThe aqueous layers were extracted with EtOAc
  9. dry with materialthe organic layers were dried (MgSO4)
  10. customEvaporation of the solvent and purification by FC (hexanes)

Quellen und Nachweise

ORD-Eintrag
ord-9c68debb65684dd389b88282ce23ba1e
Quelldatensatz
uspto-grants-2003_12
Patentnummer
US06670193B2

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